On Sun, 11 Apr 2010 04:37:04 -0700, Gunner Asch
wrote:

On Sun, 11 Apr 2010 00:17:11 -0500, Don Foreman
wrote:

On Sat, 10 Apr 2010 16:27:57 -0400, Wes wrote:

Today, I thought I'd make the rear barrel plate for my gatlingun. Simple round disk with
an array of 10 threaded holes, a central hole for a hex bushing and a dowel pin hole at 12
o'clock.

Easiest way to do this looks like I bolt the round plate to a chunk of flat stock and hold
the flat stock in my mill vise. I look around and find a 3/8 NC cap screw. Okay, I'll
use that with a washer to hold the plate down. Grab the tap stand, what is a 1/8 NPT tap
doing in the 3/8 NF hole?

Okay, I'll look for another bolt. Didn't find another bolt but I did find some 1/2 NC
threaded rod. Sweet. Back to the tap stand, there is a 5/8 NC tap in the hole for the
1/2 NC tap. I have a feeling this isn't going to be my day.

Rummage around some more, I find what I think is a 1/2-20 bolt, that would be good enough.
Check the tap stand, hey, I got a 1/2 NF tap! Check bolt to tap to see if pitch is same.
Match.

Drill and tap hole. Bolt falls into hole. ???? Look at tap stand and see there is such a
thing as a 7/16-20 fastener and by Jove I have a tap for it. I put tapped hole on other
side of plate.

Now we are cooking but I'm worrying that with a washer to bridge the 9/16" hole in my
plate, I might not have enough thread engagement since the bolt I have is rather short.
One more trip to the junk box I found the 7/16-20 bolt in and I find a FHSC in 7/16-20.
That works really well, the head centers my plate rather well over the center of the
tapped hole.

Indicate the barrel plate to find center, calculate x-y's of the 10 threaded holes and
plug away with spot drilling, drilling, chamfering and then tapping.

Unfortunately, on hole #10 I let the tap I was using go in too deep while power tapping
with the Bridgeport and the quill hit the quill stop and started to lift once side of the
flat stock I was using causing a crooked hole.

Good thing I bought extra stock. I'm going to need it.

Wes

Bummer, that eau chitte moment after some investment in labor.

I am attempting to do stress-free pillar bedding of a rifle. I've
never done it before so I'm going *very* slowly. I think I'm ready
for final goo (epoxy) but I won't do that until I've slept on it. I'd
really prefer not to have this be an oopsie. It's not an expensive
rifle but I'd still like to get it right.

Traditional goo has been acraglass, but I'm using Devcon 10110. Fitch
and I call it d22 because 10110 in binary is 22 in decimal.
(b10110=d22) It's very dense steel-filled epoxy used and advocated by
a guy who beds a lot of competition benchrest rifles.

I'm hoping to get below half-MOA (minute of arc) accuracy, i.e.
groups shot from 100 yards with max center-to-center distance of under
half an inch from this rifle. The rifle is a Savage "package rifle",
an inexpensive "consumer" off-the-rack rifle in .243. It's a sporter,
not a benchrest rifle, but it's been a shooter as found so I really
hope with some pucker that I improve it rather than screwing it up.

http://www.savagearms.com/firearms/models/

Yikes! I don't know if they're getting MSRP for these, but I paid
about half that for mine about 3 years ago, brand new, at the General
Store in Osakis MN.
http://tinyurl.com/yckr3g8

The scope was a cheap Simmons, long since replaced. Not knocking the
Savage package rifle concept, it's an excellent value. The rifle as
found with the Simmons 3-9x scope had more than sufficient accuracy
for 90% of deerhunters shooting from a tree stand. Most deer in MN
are taken at ranges of well under 100 yards.

More when (if) I can get it apart after the goo cures, get it
reassembled correctly, get the scope re-mounted and re-zeroed and see
how it shoots. It shot about 1 MOA before with 70 gn bullets, didn't
do as well with 100 gn because the rifling isn't quite steep enough to
be optimal for 100 gn. I don't care, 70 gn is ample for target and
varmints. I'd use a heavier caliber if I hunted deer.

If this turns out well then my next project will be my .22-250.

What did you use for your pillar? Monorail or seperate pillar posts?

I generally machine a monrail and bed that. Takes out stock issues (if
any). I generally use 4130 as stock for the monorail. Seems pretty
stable G. It adds maybe a pound to the total weight, if that much.

Gunner

Separate pillar posts epoxied into the stock.